Background Gamma Activity in the Electroencephalogram as a Measure of the Level of Sustained (tonic) Attention during Execution of the “Active Oddball” Paradigm in rabbits
Tonic brain activity has significant influences on the nature of a subject’s responses to target sensory stimuli. We report here studies of the dynamics of the background activity in the gamma-rhythm range of the EEG in rabbits during execution of an “active oddball” paradigm modified for animals – a task widely used for studies of attention. Increased levels of power and coherence in background gamma activity were found to reflect expectation of a target stimulus, correct responses to stimuli being executed at a particular level of background gamma activity which probably corresponds to the optimum level of sustained (tonic) attention. Decreases in the level of gamma activity led to missed responses to the target stimulus, while excess levels lead to erroneous responses to non-target signals (false anxiety). These dynamics of background gamma activity are interpreted as resulting from oscillations in the level of tonic cholinergic activation of right cerebral cortex.
The distractive effects on attentional task performance in different paradigms are analyzed in this paper. I demonstrate how distractors may negatively affect (interference effect), positively (redundancy effect) or neutrally (null effect). Distractor effects described in literature are classified in accordance with their hypothetical source. The general rule of the theory is also introduced. It contains the formal prediction of the particular distractor effect, based on entropy and redundancy measures from the mathematical theory of communication (Shannon, 1948). Single- vs dual-process frameworks are considered for hypothetical mechanisms which underpin the distractor effects. Distractor profiles (DPs) are also introduced for the formalization and simple visualization of experimental data concerning the distractor effects. Typical shapes of DPs and their interpretations are discussed with examples from three frequently cited experiments. Finally, the paper introduces hierarchical hypothesis that states the level-fashion modulating interrelations between distractor effects of different classes.
The study was devoted to the investigation of the relationships between the basic characteristics of temperament, measured by different questionnaires, and parameters of the event-related potentials recorded in a classical attentional odd-ball task.
It is well known, that even in optimal conditions animals and humans make spontaneous errors which are the most prominent manifestations of attention system failures. Our goal was to investigate the causes of attention system failures in normal state of arousal and without distracting objects. We have designed a new task which allows to answer the following question: which stage of sensory processing is compromised during attention lapses?
The heterogeneity of our visual environment typically reduces the speed with which a singleton target can be found. Visual search theories explain this via nontarget similarities and dissimilarities that affect grouping, perceptual noise, etc. Here, we show that increasing the heterogeneity of a display can facilitate rather than inhibit visual search for size and orientation singletons when heterogeneous features smoothly fill the transition between highly distinguishable nontargets. We suggest that this smooth transition reduce the “segmentability” of dissimilar items to otherwise separate subsets making the visual system to treat them as a near-homogenous sets opposing to a singleton.
The article proposes application of the level approach to attention research. Four basic principles of levelbased architecture of attention are derived from theoretical premises of the level approach to cognition and the psychology of attention as well as from empirical data. The author offers a variant of empirical research program which is based on the logic of the level approach. Finally the 5 level model of attention processes organization is proposed on the basis on experimental data. The article also contains examples of author's empirical studies which are interpreted in the level approach framework. The first study demonstrates the functioning of the redundancy principle (which is one the basic principles stated in study) in the visual inspection tasks. The second study shows the differences in the efficiency of memorizing the same material and the differences in experiencing of subjective confidence in mnemonic judgments depending on the leading level of attention in task solving.
The world that we perceive and describe changes constantly. If we believe our descriptions of the world to be accurate and consistent, we must assume that the content and the structure of our individual sentences accurately and consistently reflect the world’s constantly changing nature. If so, a comprehensive production system must model the sentence generation process taking into account this basic assumption: Words, their linear arrangement, and the structures they are inserted in must somehow reflect the corresponding parameters of the observed and described event. This system must include representation of salience as one integral component resulting in interplay that involves constant, regular, and automatic mappings between elements of a visual scene, their varying salience, and the structural arrangement of the sentence constituents and the grammatical relations between them. In this interplay, perceptual input contributes initially to this mapping process by providing information for further conceptual and linguistic encoding. Importantly, this information is not processed in an unconstrained fashion; instead, it is systematically filtered, selected, and relayed based on a regular interface between the aspects of attention and their corresponding counterparts in the conceptual and linguistic structures. Bottom-up and top-down features of this interface include noticeability, importance, or relevance. As a result, linguistic output reflects the event’s conceptual organization including the attentional state of the speaker in a regular way. This mapping between attentional focus and structural choice is a part of a more complex mapping mechanism that we will refer to as Cognition-Language Interface or CLI. Specifically, this Chapter will consider theoretical and empirical knowledge about the complex interplay between the speaker’s attentional state and the structural choices they make during sentence production.
Distractor's effect (stimulus which is irrelevant at a certain moment and ignored) on task solving efficiency is considered. It is revealed that according to problem situation and connection with target stimulus any distractor can produce two opposite effects: negative - interference and positive - redundancy effect. Distractor effects' classification based on one of possible grounds - distractor's source: sensory inputs effects, hierarchical effects and correlational effects is given. Possibility of level-hierarchical relation between the three classes of effects is discussed.
This article describes the expierence of studying factors influencing the social well-being of educational migrants as mesured by means of a psychological well-being scale (A. Perrudet-Badoux, G.A. Mendelsohn, J.Chiche, 1988) previously adapted for Russian by M.V. Sokolova. A statistical analysis of the scale's reliability is performed. Trends in dynamics of subjective well-being are indentified on the basis the correlations analysis between the condbtbions of adaptation and its success rate, and potential mechanisms for developing subjective well-being among student migrants living in student hostels are described. Particular attention is paid to commuting as a factor of adaptation.